Tutorial questions practice

so it's a solution
-

12) 5 2
2 20y 24;y
-
= 5
=
+




20t

5 be 20.5e-2t 2420t
-




y
-




=
=
- +


-
=




20 +
24 -
20/5 52-20t] 24
-
=

+




27420 t
=
24 -

24 -
20 t
24
=




is a solution

-

19)(y -
x) y y = -

x
8;y
+
x
=

4
+

z

the function?Check
of solution?
A Domain



y
x
=

4X
+ + x +


23050 X]-2

Domain is [-2,- [
=
1 4x 1
y
+
= +




2
x2 +
e



(y -

x)y1 (x = +

4y
2 -

x)(1 xz)
+




x 8
y
+
=> -




x
=



yz 42 8 x
-
-
+
+ +




8 x y x 8
y
+
+ - =
-